The present invention relates to a method for making triorganooxysilanes. More particularly, the present invention relates to a process involving the reaction of a tetraorganooxysilane in the presence of a metal hydride.
Triorganooxysilanes are silicon-containing compounds of the formula (RO)3SiH where each R independently represents a monovalent hydrocarbon group such as an alkyl group, aryl group, aralkyl group, alkaryl group, cycloalkyl group, or bicycloalkyl group. Triorganooxysilanes, are commonly made from silicon dioxide via elemental silicon. Unfortunately, elemental silicon is manufactured from silicon dioxide by an energy intensive reduction process.
The process commonly used commercially for the production of silicones and more particularly, alkoxysilanes, was first described by Rochow et al., U.S. Pat. No. 2,473,260. The Rochow process uses silicon, also referred to as elemental silicon, as a starting material. To prepare elemental silicon, silicon dioxide must be reduced. The elemental silicon is then oxidized to yield alkoxysilanes via a reaction of the silicon with methanol in the presence of a copper catalyst. It is well known in the art that the silicon-oxygen bond in silicon dioxide is extremely stable. In order to break the silicon-oxygen bond, a large amount of energy is consumed when silicon dioxide is reduced to elemental silicon. Thus, due to the large amount of energy needed to break the silicon-oxygen bond, the synthesis of silicones from silicon dioxide using the Rochow process is expensive and not energy efficient.
In the past, the controlled synthesis of triorganooxysilanes with one silicon-hydrogen bond has relied heavily on the reduction of silicon dioxide to elemental silicon. Unfortunately, the large amount of energy needed for synthesizing silicones such as triorganooxysilanes from silicon dioxide can be problematic. Thus, new synthetic routes are constantly being sought which can form silicon-hydrogen bonds.
The present invention provides a method for the preparation of triorganooxysilanes containing at least one silicon-hydrogen bond comprising reacting at least one tetraorganooxysilane with at least one metal hydride.